Methods for separating lean beef and fat and producing a product having a predetermined fat content

1. A method for separating fat from lean, comprising:

(a) transferring a mixture, the mixture comprising lean particles with frozen water, fat particles, and a fluid, through a conduit;

(b) allowing the frozen water in the lean particles to thaw as the mixture travels through the conduit and increases a density of the lean particles;

(c) transferring the mixture to a centrifuge and separating the mixture into a first stream of fat particles; a second stream of lean particles with non-frozen water, and a third stream comprising fluid;

(d) providing a housing defining a cylindrical chamber with a first end and an opposite second end;

(e) providing a piston in a sealing manner at an end of the chamber so as to provide an enclosed and sealed space between the piston and the end of the cylinder, wherein the piston can be driven towards the opposite end of the cylinder to pressurize contents in the space between the piston and the end of the cylinder; and

(f) transferring the second stream into the sealed space between the piston and the end of the cylinder.

2. The method of claim 1 , wherein the lean particles and the fat particles in the mixture in the conduit prior to thawing of the frozen water have a similar density that prevents the lean particles and the fat particles from accumulating at different elevations.

3. The method of claim 1 , further comprising adding carbonic acid solution to the mixture before step (a), wherein the carbonic acid solution has a temperature higher than the freezing point of water to thaw the frozen water.

4. The method of claim 1 , wherein the mixture comprises bones, and allowing the bones to separate from the mixture before the thawing of the frozen water.

5. The method of claim 4 , wherein the conduit comprises a vertical section and a horizontal section, and the bones are separated at a bend from the vertical section to the horizontal section.

6. The method of claim 1 , wherein the conduit comprises a vertical section and a horizontal section, and carbonic acid solution is added in the vertical section.

7. The method of claim 1 , further comprising before step (a), crushing beef particles comprising both fat and lean to produce the lean particles and the fat particles in the mixture.

8. The method of claim 7 , further comprising, before crushing, chilling the beef particles to a temperature at which the fat can crumble and separate from the lean to produce the fat particles and the lean particles.

9. The method of claim 7 , further comprising, before crushing, chilling the beef particles to a temperature at which the fat can crumble and separate from the lean while the lean remains pliable.

10. The method of claim 1 , further comprising emulsifying the fat particles into an emulsion comprising fluid and solids.

11. The method of claim 10 , further comprising separating the fluid from the emulsion via centrifugation.

12. The method of claim 1 , wherein the fluid comprises carbonic acid, and further comprising collecting the fluid with carbonic acid and heating the fluid to produce carbon dioxide gas.

13. A method for separating fat from lean, comprising:

(a) transferring a mixture, the mixture comprising lean particles with frozen water, fat particles, and a fluid, through a conduit;

(b) allowing the frozen water in the lean particles to thaw as the mixture travels through the conduit and increases a density of the lean particles;

(c) transferring the mixture to a centrifuge and separating the mixture into a first stream of fat particles; a second stream of lean particles with non-frozen water, and a third stream comprising fluid;

(d) transferring the first stream of fat particles through an emulsifier to cut the particles into smaller particles to provide a fourth stream of small particles and oil;

(e) transferring the fourth stream into a centrifuge to separate the oil any remaining lean particles to provide a fifth stream of small lean particles; and

(f) combining the fifth stream and second stream to provide a sixth stream of lean particles.

14. A method for separating solid fat from beef pieces, comprising:

(a) cooling beef pieces comprising fat and lean for a time and at a temperature that results in uneven cooling of surfaces of the fat and lean, wherein the lean is cooled to a temperature to cause freezing of water in the lean, and a surface temperature of the fat is lower than a surface temperature of the lean; and

(b) with a machine, applying pressure to the beef pieces to break the fat from the beef pieces while leaving the lean intact, wherein applying pressure comprises passing the beef pieces between a pair of parallel, adjacent, non-contacting, driven rollers, each roller having alternating recesses and protrusions around the perimeter, wherein the rollers are arranged to position a recess of one roller opposite to a protrusion of the second roller, without the rollers being in contact.

15. The method of claim 14 , wherein in step (b) the surface temperature of the fat is lower than the surface temperature of the lean by at least 5° F.

16. The method of claim 14 , wherein in step (b), the surface temperature of the lean is 26° F. or more and the surface temperature of the fat is about 5° F. or less and the surface temperature of the fat is lower than the surface temperature of the lean.

17. A method for producing a beef product having a predetermined fat content, comprising:

(a) transferring a mixture comprising a fluid, lean particles, and fat particles, through a conduit to a separating device which divides the mixture into a first lean stream, a second fat stream, and a third stream of fluid;

(b) transferring the first stream of lean particles from the separating device to a first conduit;

(c) transferring the second stream of fat particles from the separating device to a second conduit;

(d) measuring the first stream having the lean particles in the first conduit and determining a content of fat in the first stream;

(e) comparing the content of fat in the first stream with a target fat content; and

further performing (f1) or (f2);

(f1) increasing a mass flow of the second stream through the second conduit to decrease the fat content of the first stream of the mixture in the first conduit; or

(f2) decreasing the mass flow of the second stream through the second conduit to increase the fat content of the first stream of the mixture in the first conduit.

18. The method of claim 17 , further comprising measuring the mass flow of the first stream of the mixture and determining a density, and correlating the density to the fat content of the first stream of the mixture.

19. The method of claim 18 , further comprising obtaining a plurality of measurements of the massflow of the first stream of the mixture, and obtaining an average of the measurements.

20. The method of claim 17 , further comprising reducing the mass flow of the second stream of the mixture flowing through the second conduit and maintaining the mass flow constant until the fat content of the first stream of the mixture reaches a high target value, and then increasing the mass flow of the second stream of the mixture through the second conduit and maintaining the mass flow constant until the fat content of the first stream of the mixture reaches a low target value, wherein the high target value and the low target value are not the same.

21. The method of claim 20 , further comprising measuring a fat content of the second stream of the mixture and determining the constant mass flow based on the measured fat content of the second stream of the mixture.